Think you would likely have to scour garage sales and used buy/sell sites for one of those ancient portable mp3 player devices. I remember the old iRiver devices did support FLAC natively but that was before 128GB storage existed so no idea how something like that would behave when you stick in a 128+ GB SD card into it.
The other tricky part is that something that old/used may have a worn out battery so any device with a built-in battery may not stay on for very long.
The other comment makes a good point, starting out you should focus on anything that https://www.rockbox.org/ supports since that'll give you FLAC support. (besides the Archos, apparently it is impossible to play FLAC on those https://www.rockbox.org/wiki/WhyRockbox.html).
Maybe the pawn was given a meal made of human meat causing his mood to drop enough to lead to a mental break / fire starting spree?
Eventually got over that and is now hiding in his burning room because his clothes are tattered, poor guy :P